1. Field of the Invention
The present invention relates to a working machine having an apparatus that controls the operation of a plurality of actuators according to the operation of an operating member by an operator.
2. Description of the Related Art
The following techniques are known as apparatuses that control the operation of a plurality of actuators according to the operation of an operating lever by an operator.
Japanese Examined Utility Model Registration Application Publication No. 7-48761 discloses an apparatus including a plurality of hydraulic remote control valves that output a hydraulic pressure according to the operation amount of an operating lever, and pilot switching valves connected to actuators. The hydraulic pressure output from the remote control valves is input as a pilot pressure into a pilot chamber of one of the switching valves. According to circumstances, the user can switch between a plurality of combinations of the hydraulic remote control valves and the pilot switching valves by the switching operation of an operation-system switching valve interposed between the hydraulic remote control valves and the pilot switching valves.
Japanese Unexamined Patent Application Publication No. 2002-105985 discloses an apparatus that converts the operation amount of an operating lever into an electric signal, inputs the electric signal into a controller, converts the electric signal output from the controller into a hydraulic signal with an electromagnetic proportional reducing valve or the like, and inputs the hydraulic signal into one of hydraulic control valves, thereby controlling the operation of a hydraulic actuator connected to the control valve.
The apparatus of Japanese Examined Utility Model Registration Application Publication No. 7-48761 inputs the hydraulic pressure output from the hydraulic remote control valves into a pilot chamber of one of the pilot switching valves. Therefore, the apparatus can only be used for the drive control of hydraulic actuators. Therefore, in the case of a working machine having electric actuators in addition to hydraulic actuators (for example, a hybrid working machine), it is necessary to provide an additional control system for operating the electric actuators.
In the apparatus of Japanese Unexamined Patent Application Publication No. 2002-105985, of the electric signals output from the controller, electric signals used for controlling the hydraulic control valves are converted into hydraulic signals with an electromagnetic proportional reducing valve or the like. On the other hand, as for the control of electric actuators, electric signals can be used without conversion. Therefore, both hydraulic actuators and electric actuators can be operated with a common control system. However, to construct this apparatus, it is necessary to use many expensive electric components, for example, a linear encoder (or a differential transformer) for converting the operation amount of the operating lever into an electric signal, an amplifier, and solenoids in the electromagnetic proportional reducing valve. Therefore, it is inevitable that the entire apparatus is expensive compared to hydraulic control systems.
Japanese Patent No. 2914730 discloses an operating apparatus having a function as a hydraulic remote control valve that converts the operation amount of an operating lever into a hydraulic signal and controls a pilot switching valve, and a function to convert the operation amount into an electric signal in order to input the electric signal into another controlled object that is simultaneously controlled in association with the switching valve controlled by the remote control valve. However, such an operating apparatus is expensive compared to normal hydraulic remote control valves and can only be used for simultaneous associated control.